How does baseline anthropometry affect anthropometric outcomes in children receiving treatment for severe acute malnutrition? A secondary analysis of a randomized controlled trial

Mid-upper arm circumference (MUAC) < 11.5 cm and weight-for-height Z-score (WHZ) < -3 are used for screening for severe acute malnutrition (SAM). Underweight and concurrent wasting and stunting may better target those at the highest risk of mortality. We compared anthropometric outcomes in children enrolled in a trial of antibiotics for SAM based on categories of baseline anthropometry, including indicators for programme admission (WHZ < -3, MUAC < 11.5) and alternative indicators (weight-for-age Z-score [WAZ] < -3, concurrent wasting and stunting [WHZ < -3 and height-for-age Z-score < -3]). Participants were followed weekly until nutritional recovery and at 8 weeks. We evaluated changes in weight gain (g/kg/day), MUAC, and WHZ in children admitted by admissions criteria (MUAC only, WHZ only, or MUAC and WHZ) and by underweight or concurrent wasting and stunting. Of 301 admitted children, 100 (33%) were admitted based on MUAC only, 41 (14%) WHZ only, and 160 (53%) both MUAC and WHZ, 210 (68%) were underweight and 67 (22%) were concurrently wasted/stunted. Low MUAC and low WHZ children had the lowest probability of nutritional recovery (17% vs. 50% for MUAC-only and 34% for WHZ-only). There was no difference in weight gain velocity or WHZ by admissions criteria (WHZ and/or MUAC). Underweight and concurrently wasted/stunted children had lower MUAC and WHZ at 8 weeks compared with those who were not underweight or concurrently wasted and stunted. Children with both low MUAC and low WHZ had the worst outcomes. Relying on MUAC alone may miss children who have poor outcomes. Other indicators, such as WAZ, may be useful for identifying vulnerable children.